The origin of solar terms
"Twenty-four solar terms" is the product of ancient farming civilization. It is a special festival in the trunk calendar to express the change of natural rhythm and establish "December" (month). "Twenty-four solar terms" and "December" are the basic contents of the elephant trunk calendar.
The twenty-four solar terms were originally formulated according to the changes of stars. The Big Dipper consists of seven stars, including Shu Tian, Tian Xuan, Celestial Pole, Tianquan, Yuheng, Kaiyang and Yaoguang. It is named after the twists and turns of the Big Dipper.
The Big Dipper is an important astrological sign in the northern hemisphere (China is located in the northern hemisphere), and the natural rhythm of the corresponding area in the northern hemisphere changes gradually when the stars change, so it became the basis for ancient people to judge the change of solar terms.
The so-called "bucket handle refers to the east, and the world is spring; Guide to barrel handle, it's summer in the world; Bucket handle refers to the west, and the world is autumn; Bucket handle refers to the north, and the world is winter. ". Because the 24 solar terms are determined by the rotation direction of Beidou bucket handle, this calendar is also called "ephemeris".
The current "twenty-four solar terms" originated from the method of dividing according to the longitude of the sun more than 300 years ago, and it has been used since 1645. From the establishment of the constitutional calendar to the present, the "lunar calendar" and "twenty-four solar terms" are all determined according to the sun's position on the ecliptic (the degree of the sun's ecliptic).
That is to say, on a 360-degree circle "ecliptic" (the apparent path of the sun on the celestial sphere for one year), it is divided into 24 equal parts, each equal part is 15, and the spring is divided into 0 degrees as the starting point, and arranged according to the degrees of the ecliptic.
Seven-character poems of the twenty-four solar terms:
The earth goes around the sun, and it takes a year to complete a circle. A year is divided into December, and the 24 solar terms are closely linked. According to the Gregorian calendar, these two gases will not change every month. The first half of the year is June 2 1 day, and the second half is August 23 every year. These are festivals, and the difference is only one or two days. There are twenty-four sections in sequence, and the following formula is in mind.
A slight cold in January was followed by a severe cold, and it rained in early spring in February. The vernal equinox is in March and Qingming Grain Rain is in April. Long summer and full summer in May, full summer solstice in June; July is hot and slightly hot, and August is long summer, beginning of autumn; In September, the Millennium meets the autumnal equinox, and the first frost and cold dew are all in October; There is a light snow in 1 1 month in beginning of winter, and a heavy snow in winter solstice to welcome the New Year. Grasp the season and busy production, sow and harvest in time to ensure a bumper harvest.